Thermo-electric generator.



No. 839,985. PATENTED JAN. l, 1907. W. H. BRISTOL.

THERMO ELECTRIC GENERATOR.

APPLICATION FILED 133026.19055.

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@VC-mavo c o 10.839,985 EATENTEE JAN. 1, 1907.

W. E. BRISTOL. THERMO ELEOTRIO GENERATOR.

APPLICATION FILED DEG. Z6, 1905.

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. comprising a wiLL'LeM H "BRIsroL, oF NEW YORK, N. Y.

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Application ined December z6, 19o5. serial'Na 293.261.

To will whom may concern: y

Be it known that I, WILLIAM H.- BRISTOL,

a citizen of theUnited States, and a .resident of New York, inthe county of New York and` State of' New York, have invented certain new and useful Improvements inl Thermo- Electric Generators, of which the following is My invention relates to; thermo-electric generators, and particularly to thermo-electric generators as -applied to the measurement of temperature, as in thermo-electric pyrometers; and it has for its object to provide a thermo electric -generator which thou h composed of several couples of diering e ements and in series still acts as a single couple.

For this purpose my invention consists, essentially, of a thermo-electric generator primary couple or series of primary couples and one or more supplementaryl couples arranged in series therewithl and having the hot end or ends located in close proximity tothe cold end of said prima or series of primary couples, where y both the cold end of the rimary couple'or couples and the hot; endp or ends of the supplementary corlplev or couples are exposed to the same temperature, and any iiuctuations of temperature at these, points are caused to produce equivalent and opposite effects in the respective couples, and "the eleetromotive force produced by the generator as a whole isat all times dependent only upon the difference of temperature between the. hot end or ends of the primary couple or couples and the cold end of the 'supplementary couple or couples, temperature variations at intermediate 'points having 'no e'ect onthe generator as awho'le. v

The nature of my invention will be best understoodl in connection with the accompanying drawings, in whichigure 1 is a plan view of my thermo-electri c generator. Fig. 2 is-a similar view showing a number of primary couples in series and one supplementary couple. Figs. 3 to 9 are plan views showing modiications.

Similar characters of reference designate corresponding parts throughout th'e several views. f

Referring now to the drawings, my improved'g'enerator in the form shown in Fig. 1 comprises a thermo-electric couple 10, the

juncture of whoseelementsis designated by the numeral 11 and which is the hot end of Specication of Letters Patent. i

vprimary couple -Outer or cold end 14 away fromthe extreme j the generator by means of couple 12, connected in couple v v -end'11 and cold end THERMO-smoren@ eENsnA'l-on.

1 Patented Jan. 1, ,1907,

the said couple and a supplementary couple 12 Iwith the.. juncture and hot end 13.- For extremely high temperatures I make the eley ments of the prlmary couple of metals or alloys capableperatures-for example, platinum as -one element and an alloy of platinum with ten per cent. rhodium as the other element. Such metals being verylexpensive, I make `this just long enough tohave its heat and complete the supplementary series with said primary couple 10 by means of the conductors alloys capable of withstanding the semi-extreme temperatures. This supplementar couple notbeing exposed to extremely high temperatures may bel made of elements-oi cheaper metals having such' as German silverwith different percenta es of nickel, nickel alloys, iron, &c.-and w 'ch metals, because of their cheapness, may

be made of large cross-section, producing a-v lcouple of low reslstance.

The primary couple and the supplementary couple -are so arranged with respect to each other that their respective electromotive forces add,-and by further arranging the hot end 13 of the couple -12 in close proximity to the cold end 14 of the couplelO temperature variations upon the cold end 14 of the said couple 10 are made to produce equivalent opposite thermo-electric effects in the couple 12. A balance isV thus -maintained, andl vthe. thermo-electric eect of the generatoras a (whole is the same as though these points 13vv and 14 did not exist, but the generator were exposed only to the electromotive force of is de en dent'upon the ture etween its hot end 11 and its -col end 14 and the electromotive force of the cou le 12 upon the difference of temperature ethe primary 'couple 1() tween its hot end 13'and its cold end 17. As

the cold end 14 of the couple 10 is at the same temperature as the hot end 13 of the cou le 12, any variations of temperature at .t 's point will not. aiect the generator as a whole so'long as unit differences of temperature beof withstanding such tem-I temperatures at its hot 1-7. a For example,the`

lower fusing-points`l` difference of tem era- TOO tween the ends of either couple produce equivalent opposite thermo-electric effects 1n each couple. 'It is often diJ'icult, however, to select the proper elements to perfectly accomplish this result. I prefer', there- IIO fore, to approximate this condition, using la su p plementar'y couple which produces asomewhat higher electromotive force for unit dif'- :ferences of temperature than the primary couple,

A deflection 'of two hundred divisions will be produced bythe couple 10,

due to the difference of 200 Fahrenheit between its ends, and a deection of eight hundred divisions b y the couple 12, due to the difference `of 800 Fahrenheit. A total deflection of one thousand divisions isthus produced upon the indicating instrument, sincethe two couples are in series. Now let it be assumed that the tem erature atthe ends 13 and 14 drops to 700 ahrenheit. A deflection of three hundred divisions would be produced by the couple 10, owing tothe.

increased difference of temperature), and a deflection of seven hundred` divisions bythe couple 12, owing to the decreased dierence of temperature, the total deflection, however, f

still being one thousand divisions, as before, and remains*` constant irrespective of the change which has occurred at the oints, 13

\ and 14. Now let the initial con itions' be to again again assumed, but the difference of 800 between the ends 13 and 17 of the couple 12 produce a deflection of sixteen hundred divisions instead of Veight hundred, making a total deflection of eighteen hundred divisions. Assume the temperature at theends 13 and 14 drop to 700".` The couple will then produce a deflection of three hundred divisions, as before, but the couple 12 will produce a deflection of fourteen' hundred divisions, making a total deflection of seventeen hundred divisions, due to the same difference of temperature of 1000". It will thus be seen that the two indications do not correspond, notwithstanding the fact that no change of temperature has occurred at either the hot end 11 or the cold lend 17 of the thermo-electric lgenerator. to the fact that unit differences of temperature between the hot and cold ends of each couple do not produce equivalent'thermoelectric effects in the two couples, and therefore temperature variations at the ends .13 and 14 will affect the generator asa whole. To overcome this difficulty, Iernploy the aforesaid shunt, which short-circuits a part of thermo-electriceffect of the couple 12, cutting it downto make unit'differences of temperature between its ends produce thermoelectric effects equivalent to those produced by unit differences of temperature between the ends of the couple 10. The tot al effect of the generator is. therefore independent of changes of temperature at points intermeditemperature.

shunt 18 has a positiveresistance coefficient, it w1ll likewise increase w1th increase of tem-` This error is due ate of its hot end 11 and its cold end 17 and dependsonly upon variations of temperature at either of these points. The location' of the shunt 18 with respect to the couple 12 is immaterial, and I may place it acrossA the terminals 19- and 20 of said couple at intermediate points or at thehot end 13, as shown in Fig. 3. serves an additional purpose-viz., to overcome the eHects due to temperature varia-A tions at the junctions of the elements ofthe primary couple 10 with the conductors 1,5A and 16. As these conductors 15 and 16 are In this latter position the shunt.

of necessity of metals or alloys dierent from the elements of the couple 1'0, their junctions with said elements will form-secondary cou- 1 ples producing thermo-electric effects which must be made to neutralize each other, as disclosed in my prior atent, No. 764,177, of July 5, 1904, or must be compensated for, as disclosed in my copending application, Serial No.290,017, filed December 2, 1905. The

combined results of these secondary eHects is made to oppose the total effect of e generator comprising the primary and supplementary couples and to increase with increase of If, therefore, the resistanceperature, short-circuiting less of the eHect of the couple 12, and thereby compensating for the said secondary effects, as more fully set forth in the aforesaid copending application. v Instead of'making the resistance in one piece, as shown in Fig. 3, I may subdivide it, as shown in Fig. 4, the portion 18 serving to correct'for the overefect of the couple 12 and is connected across` the terminals 19 and 20 of said couple. The other portion 21 is likewise connected across the terminals 19 and 20.; but its active portion 21 is placed in close proximity to the cold end 14 and serves to compensa` e for the secondary effects at the junctions litveen the elements of the couple 10 and the nductors'` 15 and 16. Where I have occasion to make the primary couple of elements which give ,aV greater electromotive force than the supplementary coulple would if comprising but one couple, I p ace several of these supplementarycouples 12 in series, as illustrated in Fig. 5,-so as to obtain thermo-electric eects equal to or greater than er unit difference of temgerature) that o said primary couple 10. or example, should the primary couple be IOO composed of the elements anti'mony and bisequal or greater thermo-electric effect. There having the supplewould be no object .in

less eect than the *mentary couple to give a primary couple and then cut down theeflect of the latter to Correspond, as it is one of the objects of the present invention to obtain the desirable and maximum effective l'properties of the primary cou le while retaining but a minimum length oisuch couple. As

the primary couples are of-expensive material or materials which are not practicable to make of the length required and of the desired cross-section for a complete thermoelectric generator and as these materials are also usually of high resistance, it is important to make them as short as, possible and complete the generator by means of the less expensive and more substantial materials, which because of their inexpensiveness may be made of considerable cross-section to reduce the resistance.

Another advantage of the arrangement of the couple as herein disclosed is that I am enabled to use the same generator for the measurement of the temperature at different points along said generator-that is, if I take a conductor 22 from the terminal 19 in addition to the two leads 23 and 24, Fig. 6, I may by proper switching arrangement throw either the 'couple 12 or the couples 10 and 12 on one and the same indicating instrument, and thereby successively obtain the temperature at the hot end 11 or the hot end 13. I

may of course also place more than two couples in series and do not wish to restrict m self to any number of couples so arranged, as

my invention consist,l sessentially,1n so ar' ranging these couples with respect to each other that their electromotive forces may be added and produce the same effect as one single couple.

What I claim as by Letters Patent 1. A thermo-electric generator comprising; a primary couple and a supplementary coup e separate and distinct from said primary couple and in series therewith, the hot end of new, and desire to secure one couple being located in close proximity to the cold end ofthe other.

2. A thermo-electric generator comprisin a primary couple having elements of higi fusing-points; a supplementary couple se arate and distinct from said primary cou'p e having elements of lower fusing-points than said primary couple, said supplementary coulple being in series therewith and having its ot end located in close proximity to the cold end of said rimary couple.

3. A thermo-e ectric generator com a primary couple of platinum and p atinum with ten per cent. rhodium, as elements; and a supplementary couple separate and distinct from said primary couple and in series therewith having elements of iron and nickel alloy, and having its hot end located in close proximity to the cold end of said primary couple.

4. A thermo-electric generator comprising:

i couple in across said suppl of the United States, is-

its hot.end located rising:

a series of primaryouples; a supplementary series therewith, separate and distinct from said series of primary couples and having its hot end located in close` proximity to the cold end of said, series of primary couples. f

5. A thermo-electric generator comprising: a primary couple; and a number of sup lementarycouples in series therewith, saidp` series of supplementary couples being se arate and distinct from said primary coup e and having its hot end located in close proximity to the cold ends of said primary couple.

6. A thermo-electric generator comprising: a primary couple and a supplementary couple separatev and distinct from saidprimary couple and in series therewith, the hot end of one couple being located in close proximity to the cold connection withl one of said couples to com pensate for tjhe overbalancing effect of the other.

7. A thermo-electric generatorcomprising: a primary couple; a supplementary couple 1n series therewith and of' different elements from said primary couple, the hot end of one coupleI being located-in close proximity to the col end of the other and a resistance-shunt across one of lsaid couples.

8. A thermo-electric gelnerator comprisling: a primar cou e; a su ementar cou e 1n series therewih of digp y p said primar couple and having its hot end located in c oseproximit to the cold end'of said primary couple; and7 a resistance-shunt ementary couple.

9. A thermo-electric generator comprising: a primary couple having elements of high fusing-points; a supplementary cou le having elements of lower fusing-points t an said primary couple, and in series therewith and aving its hot end located in close proximity toI the cold end-of said primary cou le and a resistance-shunt across said supp ementary couple.

I 10.A A thermo-electric generator com rising: a primary couple of platinum and p atinum with ten per cent. rhodium as elements; a"supplementary couple in series therewith of iron and nickel alloy as elements, and having in close proximity to the cold end of said primary couple; and a resistance-shunt across said supplementary couple. l

11. A thermo-electric generator comprising: a series ofprimary couples; a su lementary couple 1n series therewith of d1 erent elements from said primary couples and having its hotI end located in close proximity to the cold end of said series of primary couples and a resistance-shunt across said supplementary couple.

12. A thermo-electric generator comprising: a primar couple; a number of supplementary coup es in series therewith and comerent elements froml IOO - couples.4

posedof elements different from those of said y vprimary couple, said series having its hot ments from said primary couple, having its,

ot end located in close proximity to the cold end of said primary cou le; ,and a resistanceshunt across said supp ementary couple located in close proximity to the cold'end of said primary couple.

14. A thermo-electric generator comprising: a primary couple having elements of high fusing-points; asupplementary couple having elements of lower Jfusing-points than said primary couple and in series therewith, and having its hot end located in close proximity to the cold end ofsaid primary couple ;l

and a resistance-shunt across said supplementa couple located in close proximity to the colldyend of said primary couple.

15. A thermo-electric generator com rising: a primary couple of platinum and p atinum with ten per cent. rhodium as elements; a second couple in series therewith of iron and nickel alloy as elements,- and having its hot end located in close proximity to the cold end of said primary couple; and a resistanceshunt across said supplementary couple having a portion thereof located in close prox- Aimity to the'cold end of said primary couple.

16. A thermo-electric generator compris-l ing: a series of primary couples; a sup lementary couple 1n series therewith of d1 erent elements Jfrom said primary couples and having its hot end located in close proximity to the cold end of said series of primary couples; and a resistance-shunt across said supplementar couple located in close roximity to the co d end of said v series oi) primary couples.

17. A thermo-electric generator comprising: a prima couple; a number 'of supplementary coup es in series therewith composed of elements different from those of said primary couple, said series having its hot ends located in close proximit to the cold end of said primary couple; an a resistance-shunt across said series of supplementary couples located in close proximity to the cold end of said primary couple.

18. A thermo-electric generatorcomprising: a primary couple; a supplementary coui prle in series therewith of different elements om said primary couple and having its hot end located in close proximity to the cold end of said primary couple; a resistance-shunt p across said supplementary couple; and a second resistance-shunt across said supfplementary couple, having a portion thereo located in close proximity-to the cold end of said primary couple. K

19. AI hermo-electric generator comprising: a -primary couple having elements of high fusing-pointy a supplementary couple having elements of lower fusing-points than said primary couple and in series therewith, and having its hot end located in close proximity to the cold end of said rimary couple; a resistance-shunt across sai sup lementary couple, and a second resistance-s unt across sai su pleumentary couple, having a portion thereo located in close proximity to the cold end of said primary couple.

20.l A thermo-electric generator comprising: a primary couple of platinum and platinum with ten per cent.rrhodi1`1mvas elements ;l a supplementary couple in series vtherewith of iron and nickel alloy as elements andhaving its hot end located in close proximity to 'the cold end of said primary-couple; a shunt of suitable resistance across said supplementary couple, and a second resistanceshunt across said sup lementary couple having a portion thereo? located in close proximity to the cold end of said primary couple.

21. A thermo-electric generator comprising: -a series of primary couplesya supplementary couple in series therewith of dllerent elements from said primary couples and 'having its hot end located in close proximity to the cold end of said series of primary couples; a resistance-shunt across said supplementary couple; andl a second resistanceshunt across said supplementary couple having a portion thereof located inv close proximity to the cold end of said primary couple.

22. A thermo-electric generator comprising: a primary couple; a number of supplementary couples vin series therewith, composed of elements different from those of said primary couple, said series having its hot ends located in close proximity to the cold end of said primary couple; a resistanceshunt across said series of supplementary couples; and a second resistance-shunt across said series of supplementary couples having a portion thereof located in c ose proximity to the cold end of said primary cou le. l l

Slgned at Manhattan borough, New York, in the county of New York and State of New York, this 21st day of December, A. D. 1905. y

i, WILLIAM H. BRISTOL. Witnesses :I

FREDK. F. SCHUETZ, S. 0. YUDIzKY. 

